Inverting pan conveyors capable of carrying material in the forward and return directions are known and have been used in drying machinery. In such equipment material is transferred from pans traversing a superior reach and moving in one direction of an endless conveyor to pans traversing a lower reach and moving in the opposite direction. The transfer is effected during inversion of the material carrying pans whereby material, e.g., granular material, is cascaded from an upper level to a lower level and the direction of travel is reversed. Reference may be had to U.S. Pat. No. 1,328,099 to Parkes which shows such an apparatus. In the Parkes device, the pans undergo inverson so that the same material carrying surface is presented in both directions of travel.
Similar apparatus is shown in British Pat. No. 1,109,752 published Apr. 18, 1968, British Pat. No. 538,728 dated May 7, 1895 and in French Pat. No. 944,968 published Apr. 24, 1949. Each of these shows a plurality of flat pallets having overlapping members or portions, a trailing portion of one pallet underlying the leading portion of the next adjacent pallet. When the pallet escapes a stationary hold-down, the trailing edge drops in between parallel endless conveyor chains and discharges material carried thereby to the material carrying surface of preceding pallets which have coursed around a sprocket. These pallets do not, however, undergo inversion whereby the same material carrying surface is presented in both forward and return directions as in the case of Parkes device and in the present device. Parkes effects inversion of the pans by rotating them about a transverse pallet axis in the same direction of rotation as the sprocket rotation when the pallet is moving from the upper reach to the lower reach, and in a direction of rotation counter to the sprocket rotation when moving from the lower reach to the upper reach. Parkes accomplishes inversion by means of cams mounted on the underside of the individual pallets at both ends of the pallet and coacting with stationary cam guiding troughs or brackets 19 and 30, one of which brackets is the exact negative counterpart of the other, and located on opposite sides of the apparatus.
The present invention provides a simpler structure characterized by a simplified cam and cam guide or follower system. In operation, the present structure rotates the pallets or pans oppositely with respect to the sprockets from what is taught by Parkes. Like Parkes, a plurality of conveyors may be stacked one above another in a drying apparatus.